1. Field of the Invention
The present invention relates to a seat back of an automotive seat and, more particularly, to a rear structure of the seat back in which a reinforcing rod member extended between the right and left portions in the lower portion of a frame provided in the seat back is formed in a rearwardly curved manner so as to increase the depth dimension of a seat cushion of the automotive seat.
2. Description of the Prior Art
Referring to FIGS. 1 to 3, there is illustrated an automotive seat (1) which includes a seat back designated by (2). To form the seat back (2), a reinforcing rod (4) which is curved rearwardly is provided so as to extend across the lower right and left portions of a frame (3) folded in an inverted U-shaped form, support members such as S-shaped springs are provided between the right and left side portions of the frame (3), a cushion member (10) formed of a foam material is applied to the front surface side of the frame (3), the ends of the cushion member (10) are turned back from the outer side surfaces of the frame (3) to the rear surface thereof, and all of the above-mentioned members are covered by a trim cover assembly (6) sewn in a bag-like shape. In these figures, reference numerals (14)(14) designate the turned-up or turned-back portions of the cushion member (10), respectively. As mentioned above, since the rearwardly curved reinforcing rod (4) is disposed in the lower portion of the frame (3), as shown in FIGS. 2 and 3, the depth dimension (L) of a seat cushion (5) can be increased.
Also, the turned-back portions (14)(14) of the cushion member (10) turned back to the rear surface of the frame (3), are folded back along the outside shape of the frame (3), and, in the portions where the reinforcing rod (4) is provided, it is folded back along the back surface of the reinforcing rod (4).
As mentioned above, the portions of the turned-back portions (14)(14) of the cushion member (10) where the reinforcing rod (4) is disposed provide round shapes since these portions are turned back along the curved form of the reinforcing rod (4), while the remaining portions thereof provide right-angle shapes since they are folded back along the frame (3). That is, the respective lower portions (a')(a') of the right and left corners of the rear section of the seat back (2) are formed round, and the respective upper corner portions are formed square.
Thus, in the above-mentioned conventional seat back rear structure, the shape of the rear structure of the seat back (2) lacks unity or coordination, and the trim cover assembly may produce wrinkles in the boundary portions thereof between the above-mentioned round and square-shaped corner portions, which can impair the appearance of the seat greatly.